The present disclosure relates generally to an electrostatic discharge (ESD) structure and, more specifically, to an air gap ESD structure for high speed circuits.
Many integrated circuits included in devices and systems are highly susceptible to damage from the discharge of static electricity, which has become a critical problem for the electronics industry. Accordingly, electrostatic discharge (ESD) protection is a feature included as a standard for many electronic products. Typical ESD protection circuits use an on-chip diode based ESD protection. These on-chip diode ESD devices work well for lower frequency currents but at higher speed circuits such as millimeter wave circuits, these ESD protection circuits severely impair the performance of the millimeter wave circuits because of the ESD protection circuit's inability to ameliorate the large parasitic capacitance that arises during the high operating frequency. Therefore, on chip metal tip ESD protection devices with small parasitic capacitance have been provided for high speed systems to help reduce the performance degradation caused by conventional on chip diode based ESD protection circuits.
However, conventional on chip metal tip ESD protection device can only protect the system one time because the material found between the on chip metal tips, which may be silicon oxide for example, is damaged during a protection event. Particularly, when an arc occurs during an electrostatic discharge between the metal tips, it is possible that the material found between the tips is compromised or damaged and cannot be recovered. Further, device failures that result from ESD events are not always immediately catastrophic or apparent. Sometimes, the device is only slightly weakened but is less able to withstand normal operating stresses and hence, may result in a reliability problem.
In many systems, an ESD protection device is desired to not only to pass an ESD protection test, but also to protect the system from the instant high voltage generated by a hot plug which would can occur any time. Therefore, in accordance with one approach, various single use electro-static discharge (ESD) protection circuits can be included in a device and/or system to protect the components.
Thus, there is a need for an ESD protection device that can function more than once and ideally function unlimited times to help protect the system from an electrostatic discharge.